<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>DIV+CSS</title>
	<style type="text/css">
		#box{
			font-size: 30px;
		}
		.box{
			font-size: 40px;
		}
		#box, .box{
			background: red;
			text-align: center;
		}
		.box1{
			background: green;
		}
		div .box1{
			width: 80px;
			height: 40px;
			background: #fff;
		}
		.box:hover{
			background: black;
		}
		#box:hover{
			background: #fff;
		}
		.box1:hover{
			background: red;
		}
	</style>
</head>
<body>
	<link rel="stylesheet" href="./main.css">
	<div style=width:200px;>
		<div class="box1">人生</div>
	</div>
	<div class="box">学习</div>
	<div id="box">思考</div>
	<div class="box1">交流</div>
</body>
</html>